Terminal phosphate-labeled nucleotides with improved substrate properties for homogeneous nucleic acid assays

Nucleotides with a dye attached to the terminal phosphate with four or more phosphates (tetra- or pentaphosphates) are superior substrates than the corresponding triphosphates for DNA and RNA polymerases. When fluorogenic dyes are directly attached to the terminal phosphate, they can be released by the action of polymerase and alkaline phosphatase. The released dye changes color and fluorescence properties. The fluorescent signal can also be amplified by using multiple labeled nucleotides to detect small amounts of template. We have explored the utility of these nucleotides in a variety of applications including homogeneous SNP detection methods, DNA sequencing, and quantitation of PCR and RCA.     

Spatiotemporal dynamics of shear induced bands en route to rheochaos

We show experimentally that the route to rheochaos in shear rate relaxation measurements is via Type-III intermittency and mixed mode oscillations in the shear-thinning wormlike micellar system of cetyltrimethylammonium tosylate in the presence of salt sodium chloride. Depolarised small angle light scattering measurements performed during flow show that scattered intensity temporally follows the shear rate/stress dynamics and portrays the crucial role played by nematic ordering. Direct visualization of the gap of the Couette cell, illuminated by an unpolarised laser sheet, in the (vorticity, velocity gradient) plane shows that the spatiotemporal dynamics of the shear induced structures is closely related to the temporal behaviour of shear rate/stress fluctuations.     

Anti-Osteoporotic activity of metal complexes of amine carboxyboranes

Metal complexes of trimethylamine carboxyborane successfully suppressed calcium flux from both paired pup calvaria bones and rat UMR-106 osteosarcoma cultured cells over a 48 h period. These agents increased uptake of calcium into the cell cultures and accelerated [³H]proline incorporation into collagen. Copper and iron complexes of the trimethylamine carboxyborane were more potent compared with the cobalt and chromium complexes. The agents effectively reduced Iysosomal enzyme activity and also proteolytic enzyme activities of macrophages. Since macrophages invade the bone surface and assist in the demineralization and digestion of collagen, those agents may be potentially useful to retard diseases involving bone reconstruction. Influx of white blood cells and macrophages to sites of degradation most probably would be inhibited by the agents, based on sponge test observations in mice. Osteoporosis induced by ovariectomy was minimized by injections of tetrakis[u-(trimethylamine-boranecarboxylato)-bis(trimethylamine-carboxyborane)dicopper(II)] into rats at 3.5 mg kg^?1 day^?1 for 14 days. Bone volume, density, weight and calcium content returned to normal baseline control values. In addition, the copper complex returned serum calcium, serum parathyroid hormone (PTH) and vitamin D₃ values to normal levels. One possible mode of action of these derivatives is the regulation of the production and release of chemical mediators initiating bone loss, e.g. tumor necrosis factor, TNF α and interleukins 11 or 11-2.     

Brillouin study of acoustic phonon softening and optical absorption coefficients of ultraheavily doped n-Si

The self-energies of acoustic phonons in ion implanted and laser annealed ultraheavily doped n-type Si have been measured by Brillouin scattering. The corresponding softening of the elastic constants has been estimated from the observed phonon softening and compared it with theory. At high doping levels ($\text{N}{}_{\mathrm{e}}\text{≧ 10}{}^{21}\text{cm}{}^{-3}$) the effect of the increase in atomic mass on the phonon frequency is observed in the case of doping with As. From the increase in the linewidths of the Brillouin lines with doping, the optical absorption coefficients for $\text{λ = 5145}\text{A}\text{?}$ as a function of doping are determined.     

Energy levels of the nucleus 250Bk from residual interaction studies

The bandhead energies of twenty two-quasiparticle states expected to occur in the low-energy excitation spectrum of the doubly odd nucleus ²⁵⁰Bk are calculated using a zero-range residual interaction and the results are compared with the available experimental information. Configuration assignments to nine intrinsic states reported in earlier studies are confirmed. Our calculations support the excitation energy of 115 keV for the K^π = 3⁺ state and also the characterisation of the 317 keV 5⁺ state as the K^π = 5⁺ bandhead. In addition, we suggest acceptable two-particle configurations for the 175 keV 1⁺ state and the 216 keV 0⁺ state. The expected location of eight as yet unobserved two-quasiparticle states is predicted.     

An AFVS model for polymer solutions: New scaling relationship

The altered free volume state (AFVS) approach developed by Kulkarni and Mashelkar has been extended to develop a model for the viscosity of polymer solutions. The effect of polymer concentration, molecular weight and electrolyte concentration is shown to be satisfactorily explained in the framework of AFVS model. The regimes of viscosity behaviour have been defined for the systems investigated and the transitions involved identified. The approach leads to the identification of a surprisingly simple and unique scaling parameterΦ _P, which enables excellent concentration-molecular weight superposition.     

On the principle of exchange of stabilities in the magnetohydrodynamic simple Bénard problem

The present paper establishes a new result which was long sought after in the field of magnetoconvection, namely, the validity of the principle of exchange of stabilities for the magnetohydrodynamic simple Bénard problem in the regime Qσ₁ ? π² where Q is the Chandrasekhar number and σ₁ is the magnetic Prandtl number. This result is applicable for quite general boundary conditions and provides a natural extension of A. Pellew and R. V. Southwell's (Proc. Roy. Soc. London Ser. A176 (1940), 312–343) result for the simple Bénard problem. A corresponding result for rotatory magnetohydrodynamic simple Bénard problem is also given.     

Observation of surface layering in a nonmetallic liquid

Oscillatory density profiles (layers) have previously been observed at the free surfaces of liquid metals but not in other isotropic liquids. We have used x-ray reflectivity to study a molecular liquid, tetrakis(2-ethylhexoxy)silane. When cooled to T/Tc approximately 0.25 (well above the freezing point for this liquid), density oscillations appear at the surface. Lateral order within the layers is liquidlike. Our results confirm theoretical predictions that a surface-layered state will appear even in dielectric liquids at sufficiently low temperatures, if not preempted by freezing.